Direct positive silver halide photographic light-sensitive elements

ABSTRACT

A light-sensitive, direct positive, photographic silver halide element comprising a support having thereon a silver halide emulsion layer containing a salt selected from the group consisting of a soluble salt and a complex salt of a metal belonging to Group 8 of the periodic table and a condensed polycyclic quinone compound.

United States Patent Hayakawa et al.

[151 3,656,96l Apr. 18,1972

DIRECT POSITIVE SILVER HALIDE PHOTOGRAPHIC LIGHT-SENSITIVE ELEMENTS Inventors: Yoshihide' Hayakawa, Saitama; Hideo Kawano, Kanagawa; Hirotetu Kato, Kanagawa, all of Japan Assignee: Fuji Photo Film Co., Ltd., Kanagawa, Japan 7 Filed: Jan. 7, 1970 Appl.No.: 1,302

Foreign Application Priority Data Jan. 25, 1969 Japan .,....44/5582 U.S. Cl ..96/ 10.8, 96/107 lnt.Cl ..G03c 1/28 Field of Search ..96/ 1 07, 64, 108

References Cited UNITED STATES PATENTS 2,717,833 9/1955 work... ..96/64 3,035,917 5/1962 Fryetal ..96/64 Primary Examiner-Norman G. Torchin Assistant Examiner-Richard E. Fichter Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A light-sensitive, direct positive, photographic silver halide element comprising a support having thereon a silver halide emulsion layer containing a salt selected from the group consisting of a soluble salt and a complex salt of a metal belonging to Group 8 of the periodic table and a condensed polycyclic quinone compound.

14 Claims, No Drawings DIRECT POSITIVE SILVER HALIDE PHOTOGRAPI-IIC LIGHT-SENSITIVE ELEMENTS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct positive photographic silver halide element. More particularly, it relates to a light-sensitive, direct positive, photographic silver halide element capable of providing direct positive images having low residual minimum density, a wide exposure latitude and a high contrast by only one exposure and one development.

2. Description of the Prior Art A light-sensitive, direct positive, photographic silver halide element is a photographic element wherein, as the amount of exposure applied to the element increases, the optical density of the image formed thereon after development'is reduced. It is well known that by adding a desensitizing agent to the photographic silver halide emulsion during the preparation of the photographic light-sensitive element, the reversal sensitivity speed is markedly increased.

As the aforesaid desensitizing agents, there are known such organic compounds as pinakryptol yellow and pinakryptol green, and compounds which contain a metal of Group 8 of the Periodic Table, such as rhodium and iridium compounds (see,e.g.,U.S. Pat. No. 2,717,833).

However, in conventional light-sensitive, direct positive, photographic silver halide elements inwhich the aforesaid known desensitizingagents are utilized, an effect known as the Herschel effect occurs, and hence the sensitivity is low. It is also necessary to expose the light-sensitive element to light through a yellow filter. That is, if a yellow filter is not used during the exposure of the light-sensitive element, no positive images are obtained or, if any positive images are obtained, they are inferior in quality. In this case, the above-mentioned occurrence of the inferior image quality is caused by the fact that a negative image is formed by a so-called re-reversal phenomenon, thatis, a phenomenon wherein as the amount of exposure increases, the optical density of the formed images after development is increased again over the minimum value and the negative image thus formed is superposed on the positive image.

Therefore, an object of the present invention is to providea light-sensitive, direct positive, photographic silver halide element having a wide exposure latitude and being capableof providing hard direct positive images having high contrast.

SUMMARY OF THE INVENTION According to the present invention, a salt of a metal belonging to Group 8 of the periodic table and a condensed polycyclic quinone are incorporated into the photographic lightsensitive emulsion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The metals belongingto Group 8 of the periodic table which may be employed in the present invention include rhodium, iridium, ruthenium, palladium, osmium, cobalt, and platinum.

The metals may be employed in the formof water-soluble naphthoquinone, anthraquinone, phenanthraquinone, and

derivatives thereof. The following are particularly preferable: sodium anthraquinone-2,6-disulfonate, a-naphthoquinone, 2- chloroanthraquinone, sodium anthraquinonel3 -sulfonate, l,5-dichloroanthraquinone, and l,2-benzanthraquinone.

The photographic silver halide emulsion to which the aforesaid compounds are added consists of a protective colloid such as gelatin or a hydrophilic organic colloid having dispersed therein silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver chlorobromide, or silver chloroiodobromide.

The above-mentioned salt of the Group 8 metal is incorporated in the aforesaid silver halide photographic emulsion during the emulsification of the silver halide or during physical ripening of the photographic emulsion. The preferable amount of the metal salt to be added is from 1 X 10 mole to l X 10 mole, particularly from 1 X 10 mole to l X 10 mole, per 1 mole of silver halide.

The amount of the condensed polycyclic quinone to be used with the above-mentioned metal salt depends upon the nature of the polycyclic quinone and silver halide emulsion to be employed but is preferably from 5 mg. to 500 mg. per 1 mole of silver halide. The condensed polycyclic quinone may be added in the silver halide emulsion at any stage but is most preferably added thereto at a stage after the completion of the formation of fogged nuclei and before coating. The condensed polycyclic quinone may be added to the photographic silver halide emulsion while dissolved in a solvent that has no deleterious effect on the emulsion, such as water, a lower alcohol having from one to five carbon atoms, or a ketone.

In the present invention, better results may be obtained by using, together with the two ingredients mentioned above, a known desensitizing agent such as pinakryptol yellow, pinakryptol green, or phenosafranine. This third ingredient is preferably added to the silver-halide emulsion just before coating.

The direct reversal silver halide photographic light-sensitive element ofthe present invention may be prepared in the following manner. A silver halide emulsion is prepared according to a conventional method of precipitation and physical ripening, fon'ning fogged nuclei in the silver halide emulsion by exposing or by alkalifying the silver halide emulsion and adding thereto a reducing agent such as formaldehyde, hydrazine, a divalent tin salt, thiourea dioxide, or an amine compound. Thereafter, the emulsion is applied to a suitable support, after adding thereto the aforesaid metal salt and the condensed polycyclic quinone together with, if necessary, the abovementioned desensitizing agent. The support may be a cellulose acetate film, a polyethylene terephthalate film, a barytacoatedpaper, a synthetic paper, or a waterproof paper. Then, the assembly is dried. Moreover, ordinary photographic additives such as hardening agents, surface active agents, and sen- EXAMPLE l To a 10 percent aqueous gelatin solution were added simultaneously an aqueous solution containing g. of silver nitrate and an aqueous solution containing 30 g. of sodium chloride, 20 g. of potassium bromide and 10 mg. of rhodium chloride to form fine silver halide particles. Thereafter, 1 g. of potassium iodide and 40 g. of gelatin were added to the silver halide emulsion and then the pH of the emulsion was adjusted to 9.5 with sodium carbonate. Then, 3 ml. of a 1 percent aqueous hydrazine chloride solution was added to the emulsion and the resultant emulsion was ripened for 40 minutes to form fogged nuclei. After ripening, the pH of the silver halide emulsion was adjusted to 6.0 with a 10 percent aqueous citric acid solution. The resultant silver halide emulsion was cooled, washed with water, and sodium anthraquinone-2,6-disulfonate together with. pinakryptol yellow in the amounts shown in Table l were added to the emulsion. As a control example,

photographic silver halide emulsions were prepared in a similar manner as above except that no rhodium salt was added.

TABLE 1 Concentration of Ingredients Emulsion Rhodium Sodium anthraquinone- Pinakryptol No. chloride 2,6-disulfonate yellow 1 0 100 2 0 200 0 (note): the unit ofconcentration is mg./l mole ofAg.

Each of the photographic silver halide emulsions prepared above was coated on a cellulose trlacetate film and dried.

The light sensitive, direct positive, photographic films prepared above were exposed through an optical wedge to a tungsten lamp' of 2,660 K. and developed for 3 minutes at 20 C. in a developer having the following composition:

Water 500 ml. Sodium sulfitc (anhydrous) 30 g. Paraformuldehydc 7,5 g. Borax 7.5 g. Sodium bisulfite 2.2 g. Hydroquinone 22.5 g. Potassium bromide 16 g. Water to make 1.000 ml.

The minimum density, the contrast, and the exposure latitude ofthe samples prepared are shown in Table 2.

TABLE 2 Test Minimum density Contrast Exposure latitude No.

The contrast shown in the above table is the mean gradient between point 1 (base density of characteristic curve fog density density 0.1) and point 2 (base density of characteristic curve fog density density 2.1). I

The exposure latitude in the above table is shown by the difference (log E log E,) between logarithms of the exposure amount log E giving (base density fog density density 2.1) ofthe negative image portion, and the exposure amount log E giving (base density fog density density 2.1)ofthe positive image portion.

From the results shown in Table 2, it is readily apparent that samples 6 and 7 had much wider exposure latitudes, higher contrast and lower minimum density than the other samples.

EXAMPLE 2 To a 10 percent aqueous gelatin solution were added, simultaneously, an aqueous solution containing 100 g. of silver nitrate and an aqueous solution containing 30 g. of sodium chloride, 20 g. of potassium bromide, and 10 mg. of iridium chloride, to thereby form fine silver halide particles. Thereafter, 1 g. of potassium iodide and 40 g. of gelatin were added to the silver halide emulsion and the pH of the resultant emulsion was adjusted to 9.5 with sodium carbonate.

After adding 5 ml. of a 0.1 percent aqueous thiourea dioxide solution, the emulsion was ripened for 40 minutes to form fogged nuclei and then the pH of the emulsion was adjusted to 6.0. After cooling and washing with water, 2- chloroanthraquinone and pinakryptol yellow were added to the emulsion as shown in Table 3. Also, as control samples,

similar silver halide emulsions containing no iridium chloride were prepared by a method similar to the above method.

Each of the photographic silver halide emulsions thus prepared was coated on a polyethylene terephthalate film and dried. The light-sensitive films thus prepared were exposed and developed as in Example 1. The results (the minimum density, contrast and the exposure latitude) are shown in Table 4.

TABLE 3 (mg/mole Ag) Concentration of Ingredients Emulsion Iridium Z-chloro- Pinakryptol No. chloride anthraquinone yellow 1 0 0 2 0 200 0 3 0 100 50 4 20 0 0 5 20 0 100 6 20 200 0 7 20 100 50 TABLE 4 Test Minimum density Contrast Exposure Latitude No.

From the results shown in Table 4, it is apparent that samples 6 and 7 had an extremely wider exposure latitude, lower minimum densities and higher contrast than the other samples.

What is claimed is:

l. A light-sensitive, direct positive, photographic silver halide element comprising a support having thereon a silver halide emulsion layer containing a soluble nitrate, halide, or a complex salt of a metal selected from the group consisting of rhodium, iridium, ruthenium, palladium, osmium, cobalt and platinum, and

a condensed polycyclic quinone compound.

2. The light-sensitive, direct positive, photographic silver halide element as in claim 1 wherein said complex salt is represented by the formula A MX wherein A represents an alkali metal or a hydrogen atom, M represents rhodium, iridium, ruthenium, palladium, osmium, cobalt or platinum, and X represents a halogen atom.

3. The light-sensitive, direct positive, photographic silver halide element as in claim 1 wherein said condensed polycyclic quinone is selected from the group consisting of sodium anthraquinone-2,6-disulfonate, a-naphthoquinone, 2- chloroanthraquinone, sodium anthraquinone- B -sulfonate, 1,5-dichloro-anthraquinone, and 1,2-benzanthraquinone.

4. The light-sensitive, direct positive, photographic silver halide element as in claim 1 wherein said salt is incorporated in said silver halide photographic emulsion during the emulsification or physical ripening of said silver halide emulsion and wherein said condensed polycyclic quinone is incorporated in said silver halide photographic emulsion at a stage after the completion of the formation of fogged nuclei and before the coating of said emulsion onto said support.

5. The light-sensitive, direct positive photographic silver halide element as in claim 1, wherein the amount of said salt in said emulsion layer is from 10 mole to 10 mole, per 1 mole a soluble nitrate, halide, or a complex salt of a metal selected from the group consisting of rhodium, iridium, ruthenium, palladium, osmium, cobalt and platinum,

a condensed polycyclic quinone, and

a desensitizing agent.

8. A light-sensitive direct positive, photographic silver halide element as in claim 7 wherein said complex salt is represented by the formula v 1 A,MX wherein A represents an alkali metal or a hydrogen atom, M represents rhodium, iridium, ruthenium, palladium, osmium, cobalt or platinum, and X represents a halogen atom.

9. The light-sensitive, direct positive, photographic silver halide element as in claim 7 wherein said condensed polycyclic quinone is selected from the group consisting of sodium anthraquinone, a-naphthoquinone, 2-chloroanthraquinone, sodium anthraquinone- B -sulfonate, 1,5-dichloroanthraquinone, and l,2-benzanthraquinone.

10. The light-sensitive, direct positive, photographic silver halide element as claimed in claim 7 wherein said salt is incorporated in said silver halide emulsion during the emulsification or physical ripening of said silver halide emulsion and wherein said condensed polycyclic quinone is added to said silver halide emulsion at a' stage after the completion of the formation of fogged nuclei and before the coating of said emulsion onto said support.

11. The light-sensitive, direct positive photographic silver halide element as in claim 7 wherein said desensitizing agent is selected from the group consisting of pinakryptol yellow,

' pinakryptol green and phenosafranine.

12. The light-sensitive, direct positive, photographic silver halide element as in claim 7 wherein said desensitizing agent is incorporated in said silver halide emulsion just before the silver halide emulsion is applied to said support.

13. The light-sensitive, direct positive, photographic silver halide element as in claim 7, wherein the amount of said salt in said emulsion layer is from 10 mole to 10 mole, per 1 mole of silver halide.

14. The light-sensitive, direct positive, photographic silver halide element as in claim 7, wherein the amount of said quinone compound in said emulsion layer is from 5 mg. to 500 mg., per 1 mole of silver halide. 

2. The light-sensitive, direct positive, photographic silver halide element as in claim 1 wherein said complex salt is represented by the formulaA2MX6 wherein A represents an alkali metal or a hydrogen atom, M represents rhodium, iridium, ruthenium, palladium, osmium, cobalt or platinum, and X represents a halogen atom.
 3. The light-sensitive, direct positive, photographic silver halide element as in claim 1 wherein said condensed polycyclic quinone is selected from the group consisting of sodium anthraquinone-2,6-disulfonate, Alpha -naphthoquinone, 2-chloroanthraquinone, sodium anthraquinone- Beta -sulfonate, 1, 5-dichloro-anthraquinone, and 1,2-benzanthraquinone.
 4. The light-sensitive, direct positive, photographic silver halide element as in claim 1 wherein said salt is incorporated in said silver halide photographic emulsion during the emulsification or physical ripening of said silver halide emulsion and wherein said condensed polycyclic quinone is incorporated in said silver halide photographic emulsion at a stage after the completion of the formation of fogged nuclei and before the coating of said emulsion onto said support.
 5. The light-sensitive, direct positive photographic silver halide element as in claim 1, wherein the amount of said salt in said emulsion layer is from 10 6 mole to 10 2 mole, per 1 mole of silver halide.
 6. The light-sensitive, direct positive, photographic silver halide element as in claim 1, wherein the amount of said quinone compound in said emulsion layer is from 5 mg. to 500 mg., per 1 mole of silver halide.
 7. A light-sensitive, direct positive photographic silver halide element comprising a support having thereon a silver halide emulsion layer containing a soluble nitrate, halide, or a complex salt of a metal selected from the group consisting of rhodium, iridium, ruthenium, palladium, osmium, cobalt and platinum, a condensed polycyclic quinone, and a desensitizing agent.
 8. A light-sensitive direct positive, photographic silver halide element as in claim 7 wherein said complex salt is represented by the formulaA2MX6 wherein A represents an alkali metal or a hydrogen atom, M represents rhodium, iridium, ruthenium, palladium, osmium, cobalt or platinum, and X represents a halogen atom.
 9. The light-sensitive, direct positive, photographic silver halide element as in claim 7 wherein said condensed polycyclic quinone is selected from the group consisting of sodium anthraquinone, Alpha -naphthoquinone, 2-chloroanthraquinone, sodium anthraquinone- Beta -sulfonate, 1,5-dichloroanthraquinone, and 1,2-benzanthraquinone.
 10. The light-sensitive, direct positive, photographic silver halide element as claimed in claim 7 wherein said salt is incorporated in said silver halide emulsion during the emulsification or physical ripening of said silver halide emulsion and wherein said condensed polycyclic quinone is added to said silver halide emulsion at a stage after the completion of the formation of fogged nuclei and before the coating of said emulsion onto said support.
 11. The light-sensitive, direct positive photographic silver halide element as in claim 7 wherein said desensitizing agent is selected from the group consisting of pinakryptol yellow, pinakryptol green and phenosafranine.
 12. The light-sensitive, direct positive, photographic silver halide element as in claim 7 wherein said desensitizing agent is incorporated in said silver halide emulsion just before the silver halide emulsion is applied to said support.
 13. The light-sensitive, direct positive, photographic silver halide element as in claim 7, wherein the amount of said salt in said emulsion layer is from 10 6 mole to 10 2 mole, per 1 mole of silver halide.
 14. The light-sensitive, direct positive, photographic silver halide element as in claim 7, wherein the amount of said quinone compound in said emulsion layer is from 5 mg. to 500 mg., per 1 mole of silver halide. 